Newborn Screening and NBS Disorders

Professor: Melanie S. Campbel, MAN RN
Date: 3/14/2026

Learning Objectives

1. Definition and Significance of Newborn Screening (NBS)

   • Newborn Screening is a standardized procedure performed shortly after birth to detect heritable congenital metabolic disorders that are not clinically apparent but can lead to serious physical complications, mental retardation, or death if untreated.

   • Significance: Ensures every infant has access to early detection and intervention, preventing lifelong disabilities.

   • Governed by RA 9288 (Newborn Screening Act of 2004), which integrates NBS into the public health system.

   • Key components of the act:

     • Integration of NBS into the public health delivery system.

     • Requirement for health practitioners to inform parents of the procedure.

     • Establishment of the Newborn Screening Reference Center (NSRC).

     • Provision for newborn access to screening and sustainable systems.

     • Awareness of advantages among health practitioners.

     • Recognition of parental responsibility regarding newborn screenings.

2. Optimal Timing for NBS Collection

   • Ideal Timing: 48 to 72 hours post-birth.

   • Earliest Timing: Can be conducted as early as 24 hours after birth.

   • For High-Risk Newborns: If in the Neonatal Intensive Care Unit (NICU) and unable to meet the 72-hour requirement, they must be tested by 7 days of age.

3. Specimen Collection for Screening

   • Heel Stick Method: Puncture the lateral heel to obtain large drops of blood.

   • Guthrie Card Use: Blood is dripped onto special filter paper ensuring complete saturation.

   • Drying Process: Sample must be air-dried for at least 3 hours; do not use heat or sunlight for drying.

4. Nursing Responsibilities & Management

   • Pre-Procedure Actions:

     • Verify consent.

     • Inform parents that NBS is a standard of care.

   • During Procedure:

     • Provide infant comfort (non-nutritive sucking, swaddling).

     • Ensure correct saturation of Guthrie card.

   • Post-Procedure Actions:

     • Document the time and date of blood collection.

   • Management of Results:

     • Normal Results: Sent to the facility and parents can claim them.

     • Positive Results (Recall): Immediate notification of family required for confirmatory testing.

Heritable Disorders Identified by NBS

1. Congenital Hypothyroidism

   • An endocrine disorder, also known as cretinism or dwarfism.

   • Caused by

     • Absence or underdevelopment of the thyroid gland.

     • Resulting in insufficient thyroxine for metabolism and growth.

   • Consequences if Not Treated:

     • Stunted physical growth, potential irreversible mental retardation if not diagnosed within 4 weeks postpartum.

   • Treatment:

     • Lifelong thyroid hormone replacement therapy starting as soon as possible after diagnosis, usually a single morning dose.

     • Drug of Choice: Synthetic Levothyroxine (e.g., Synthroid, Proloid, Levothroid).

     • Outcomes of Early Treatment:

     • Normal physical growth and intelligence if treated promptly.

2. Congenital Adrenal Hyperplasia (CAH)

   • Caused by a defect in adrenal cortisol biosynthesis, leading to severe salt loss, dehydration, and excess male hormones.

   • Symptoms Onset: Symptoms begin shortly after birth; may include:

     • Anorexia, progressive weight loss, vomiting, dehydration.

     • Disturbances in cardiac rate, cyanosis, and dyspnea.

     • Risk of infant mortality within weeks if untreated.

   • Treatment:

     • Hormonal replacement with hydrocortisone for glucocorticoid therapy, along with mineralocorticoid therapy for salt-wasting forms.

3. Phenylketonuria (PKU)

   • Inborn error of metabolism due to lack of the enzyme phenylalanine hydroxylase.

   • Leads to the buildup of phenylalanine in serum, causing brain damage and mental retardation.

   • Physical Signs: Late physical signs include absence of melanin pigment, resulting in blond hair, fair skin, and blue eyes.

   • Therapeutic Management:

     • Dietary protein restriction.

     • Maintain serum phenylalanine levels within a safe range (2-8 mg/dL) to avoid brain damage (11-15 mg/dL).

     • Use special milk substitutes and low-protein breast milk.

     • Dietary management is lifelong, with no high protein or dairy products allowed.

     • Pregnancy Advisory: Pregnant mothers should adopt a low phenylalanine diet.

   • Nursing Care Management:

     • Monitor diet and encourage compliance to avoid temptation from peer pressures.

     • Involve children in meal planning and provide rewards.

     • Support family and monitor development physically, neurologically, and intellectually.

4. Galactosemia

   • Type 1: Deficiency in Galactokinase affects the conversion of galactose to glucose, leading to galactosemia and galactosuria.

     • Complications: mental deficiency, cataracts, death if untreated.

     • Dietary Treatment: Galactose-free diet (elimination of milk products essential).

   • Type 2 (Classic): Severe deficiency in Uridyl Transferase that presents with early symptoms such as jaundice, vomiting, enlarged liver and spleen, hypoglycemia, convulsions, and feeding difficulties.

     • Complications: Liver cirrhosis, irreversible mental retardation.

     • Dietary Treatment: Exclusion of all sources of galactose to prevent severe complications.

5. G6PD Deficiency

   • Deficiency of G6PD leads to red blood cell vulnerability against oxidative substances.

   • Results in severe anemia and hyperbilirubinemia, with risks of kernicterus (jaundice of the brain), convulsions, coma, and potentially death.

   • Hemolysis Triggers: Includes certain drugs (e.g., sulfonamides, quinolones), chemicals (e.g., mothballs), and foods (e.g., fava beans).

6. Maple Syrup Urine Disease (MSUD)

   • An autosomal recessive inherited disorder where the body cannot process certain amino acids.

   • Symptoms: Sweet odor of urine, poor feeding, vomiting, lethargy, and developmental delays.

     • Untreated MSUD can lead to seizures, coma, and death.

   • Dietary Treatment:

     • Maintain a protein-free diet with a formula low in leucine, isoleucine, and valine.

     • IV amino acids that do not contain branched-chain amino acids combined with glucose for energy.

Expanded NBS

• Effects if Screened and Managed:

  • Disorders managed through proper screening results in normal development with episodes of manageable metabolic crises.

• Consequences if Not Screened:

  • Failure to screen can lead to developmental delays, breathing issues, neurologic damage, seizures, coma, or early death.

Summary of Clinical Manifestations

Treatment Summary